Diversity, distribution and abundance of insect pests associated with western Himalayan oaks (Quercus spp) in Himachal Pradesh

Oak forests are a vital component of the western Himalayan ecosystem, providing essential services such as soil and water conservation, biodiversity support and livelihood sustenance. These forests are increasingly threatened by insect pests, biotic pressures and climate change. The present study assessed the diversity, abundance and seasonal dynamics of insect pests in oak forests of Himachal Pradesh, western Himalaya. Surveys were conducted at 25 oak-dominated sites across six districts during pre-monsoon, monsoon and post-monsoon seasons from October 2019 to March 2022. A total of 107 insect pest species belonging to 38 families and seven orders were recorded. Lepidoptera was the most dominant order in terms of abundance and richness, followed by Coleoptera and Hemiptera. Pest abundance peaked during the monsoon season, though diversity and evenness varied among sites, with Chamba and Kinnaur showing higher diversity despite lower abundance. Lepidopteran defoliators caused the most severe damage, while borers and sap-sucking insects affected multiple plant parts. The results indicate increasing pest pressure on Himalayan oak forests, emphasizing the need for regular monitoring and integration of pest management strategies into forest conservation programmes.